Recliner assemblies are well-known devices which can be installed on a motor vehicle seat assembly and provide for forward and rearward reclining movement of a seat back structure through a range of reclining positions. Such recliner assemblies utilize various constructions in order to provide this reclining movement.
U.S. Pat. No. 4,348,050 discloses an example of a conventional ring-type recliner in which a pair of generally circular locking rings and a number of slidable locking members are used in order to prevent and allow forward and rearward reclining movement of a seat back with respect to a seat structure. The two coaxial locking rings have teeth disposed about their inner circumference and are disposed adjacent to one another. When the recliner assembly is in the locked position, the sliding locking members engage the teeth on both locking rings to thereby ensure that forces applied to the seat back structure are transmitted to the seat structure through the sliding locking members. A rotating circular cam member is disposed centrally with respect to the locking rings such that rotation of the cam member in a locking direction slides the sliding locking members radially outwardly into engagement with the two locking rings.
In order to release the recliner assembly and allow for a reclining movement of the seat back, the camming member is rotated to a released position and the application of force in a forward or rearward reclining direction to the seat back causes rotation of the locking ring associated with the seat back relative to the locking ring associated with the seat structure such that the movement of the teeth cam the sliding locking members out of engagement with both locking rings. This construction, however, is undesirable in that the camming action required to slidably move the sliding locking members out of engagement with the teeth on the locking rings will wear down the surfaces of the teeth on both the rings and the locking members over a period of repetitive usage. Also, debris and foreign objects which may find their way into the recliner assembly may jam one or more of the locking members and cause one of them to stick, thereby giving an occupant a false indication that the recliner assembly is in a locked position when he applies pressure to the seat back and the seat back fails to move. In this situation, the jammed locking member may unjam and thereby unlock the recliner assembly during high force conditions, such as a collision, thereby presenting a potentially unsafe situation.